these things. he forged his parents' signatures on loan applications. >> reporter: and the government is using this guy to testify. >> exactly. he ended up getting 20 years in prison while i got 21. >> reporter: he sent a statement saying, mr. engle was convicted by a jury of fraudulently obtaining more than $1 million in four mortgage loans. that same office also fostered a case of more than $2.9 billion. somehow, those banks so hungry for those liar loans, by and large escaped criminal prosecution. >> reporter: what surprises me as somebody who has kept a pretty close eye on this over the last dozen years how people at the top of the food chain had to take a fall or been prosecuted or that the government even tried to go after them. why is that? >> you know, that is the $64,000 question. i think if you were to ask the folks in washington, they will tell you that there is a lot of behavior that while it was unethical and perhaps morally suspect didn't rise to the level of criminal conduct. >> reporter: is it sometimes just easier to go to the guy who is on the bottom of the food chain? >> it'